   children with a vector of the last n events, from oldest to newest. Ignores
   event times. Example:
 
-  (moving-event-window 5 (combine folds/mean index))"
+  (moving-event-window 5 (smap folds/mean index))"
   [n & children]
   (let [window (atom (vec []))]
     (fn stream [event]

  calls children with a vector of those events, from oldest to newest. Ignores
  event times. Example:

  (fixed-event-window 5 (combine folds/mean index))"
  [n & children]
  (let [buffer (atom [])]
    (fn stream [event]

  interval seconds."
  [interval event-key folder & children]
  (part-time-fast interval
                  (fn create [] (atom []))
                  (fn add [r event]
                    (when-let [ek (event-key event)]
                      (swap! r conj event)))
                  (fn finish [r start end]
                    (let [events @r
                          stat  (folder (map event-key events))
                          event (assoc (last events) event-key stat)]
                      (call-rescue event children)))))

(defn fold-interval-metric
  "Wrapping for fold-interval that assumes :metric as event-key."
